Contrary to the popular belief that it only took a few thousand years for Mars to cool and solidify from an initially molten ball, their study suggests that there was a thick steam atmosphere on Mars very early in the planet's history that kept the surface a magma ocean for 100 million years - and essentially sterile the whole time.

'The toughest extremophile bacteria on Earth can withstand up to 130 degrees Celsius, so that makes it very difficult to see how life could have evolved under the conditions on primeval Mars,' said O'Neill.

'The conditions for life wouldn't have existed, unless you could really handle the heat,' he added.

These results were recently published in Nature Geoscience.